Attention! The light has gone!

2009/09/01 Lakar Iraizoz, Oihane - Elhuyar Zientzia Iturria: Elhuyar aldizkaria

• Teknologia
• Energia
• Elektronika

Suddenly, the darkness has been imposed on the house. "Look! The light has gone!" we think and are heading in search of a flashlight or a candle to know where we are going at home and do no cowboy. We have no choice but to wait until the light returns.

We consider it a fact at once. However, for the managers of the electric grid, any blackout is an emergency that needs to be solved and follows a protocol to reset the electricity supply as soon as possible.

They perform periodic simulations to improve reaction time and efficiency in situations of possible gravity. They also simulate extreme emergencies to be clear about what to do and how to do it, for example, if a whole state is without light. In this extreme situation, the first job is to recover the state of security. In order to do this, those responsible for the Nuclear Security Council should first be informed of what happened, so that they can stop the electricity generation in the nuclear power plants with the lowest possible risk.

It is very important to stop the generation of electricity when the supply is interrupted: if there is nothing that consumes that electricity, the appliances that are producing electricity are heated and the heating can cause very serious problems in the facilities and especially serious in the nuclear power plants.

In addition to ensuring safety, it is necessary to restore the entire supply. This work is done gradually so that at every moment the amount of electricity that is being generated is the same as the one necessary to consume.

This is a work to be carried out in a very coordinated and synchronized way, since in case of imbalance other electrical interruptions can occur. If the consumption connected to a specific line increased considerably, it would overload and pass more current than it could bear. Since this excessive current can burn some transformer, cables or other component of the network, protections are placed: from a certain current level, protections are activated and electricity is interrupted. As the house differentials.

If the generation were greater than the consumption, the problems would be with the network voltage: as the voltage must always be at certain intervals, the excessive increase would put in place other protection systems and a new blackout would occur.

The ramification, fundamental

Simulating simulations, the reality is very difficult to produce blackouts at the state level, at least in Spain and France, where the electricity network is heavily branched. The transport network is especially ramified, that is, the network that transports this electricity from facilities that generate a lot of electricity to the consumption zones. There are numerous electricity generating facilities and the lines that leave one and the other are interconnected with each other. Therefore, if any failure fails, they satisfy the need for electricity with the generation of other power stations.

However, there are networks that are not as ramified as ours, so they sometimes have serious problems. For example, Italy has a quite vulnerable network, on the one hand because it is not very ramified, and on the other, because it brings a lot of electricity from outside, among other things, it receives two important lines from France and Switzerland.

Well, in 2003, most of Italy was left unlit by an accident in Switzerland. The Swiss line failed and could not transport anything. In this situation they had to pass the necessary electricity through the French line. And of course, as this line is designed to pass a certain current, due to overload they also failed.

More common in the distribution network

The failures in the transport network make it difficult for a blackout to occur as large as that occurred in Italy. On a smaller scale, however, they are sometimes given. Most of the blackouts are produced in the distribution network, that is, in the lines that bring electricity to consumers from substations. These lines are not usually so ramified and in case of sinister, yes, electricity can not reach.

The blackouts are caused mainly by storms, by the fall of some tree on some line, by wind damage in some tower or by spilling, by lightning fall in some line, etc. In these cases, it is very common for a neighborhood, a town or a group of villages to remain without light. Thousands of users witnessed an example of this type in January, when we had an explosive cyclogenesis.

The repair of these small claims and the replacement of the electrical supply is not usually a complicated task, since there is usually no generation in these networks, so a gradual synchronization is not required. Yes, until the failure is solved, there are many regions that must be adapted without light.